Mechanical tuning device



Feb, 25, 1941. TYZZER 2,233,330

MECHANICAL TUNING DEVICE Filed April 7, 1938 INVENTOR. flown/Pa J Z' zzaa MAWQ M A TToRNEYs,

Patented Feb. 25 194 1 PATENT OFFICE MECHANICAL TUNING DEVICE Howard J. Tyzzer, Cincinnati, Ohio, assignor to The Crosley Corporation, Cincinnati, Ohio, a

corporation of Ohio Application April 1, 1338, Serial No. 206,731

14 Claims.

My invention is addressed to tuning mechanism for radio sets wherein, although the set may be tuned in the regular manner if desired, the actuation of mechanical selective means instantly 5 tunes in certain predetermined stations for which the mechanism has been set. In the particular embodiment of my device which I shall hereinafter describe, there is a series of push buttons 10 station. The depressing of one of these plungers at once brings in the desired station. This is a matter ofgreat convenience in a home radio set; but is also a matter of safety in an automobile radio set. As taught in my copending application Ser. No. 200,730 and entitled Automotive radio apparatus,*I am now making automobile radio sets which are placed beneath the instrument panel of an automobile and which have, on the face of the instrument panel, not only the usual dial and manual tuning knob but which also have a series of plungers for the purpose described. The operation of tuning the radio set to the preselected stations is not only made very much more rapid, but need not take the a device of this character makes for safer driving.

In the practice of my invention I preferably employ certain of the principles set forth in my copending application Ser. No. 226,520, filed Au- 7 gust 24, 1938, and entitled a Push button tuning device, which is a division of my application'of the same title, Ser. No. 192,258, filed February 24, 1938. Objects'of the present invention are the provision of mechanical tuning means which are much less expensive than those.

and which, albeit accurate in operation, does not require great accuracy of formation of the component parts.

These and other objects of my invention which will be set forth hereinafter or will be apparent to one skilled inthe art upon reading these specifications I accomplish by that certain construction and arrangement of parts of which I shall now set forth an exemplary embodiment,

or plungers, each appropriate to a preselected drivers attention away from his driving. Thus Fig. 3 is a perspective view of a form of plunger 10 assembly which I may use.

It is convenient to manufacture as a single unit, in accordance with my invention, the combination of condenser or gang condenser and the tuning apparatus. The unit thus produced can then be installed in a radio set by mounting it upon or building it into the chassis of the set. In the particular embodiment here illustrated a gang of two condensers is shown; but fewer or more condensers may be employed.

In the practice of my invention I make a frame or box having a. base i, a back piece 3, end pieces 4 and '5 and a forward piece 6. An extension of the forward piece is'bent over as at l and again as at 0 to form, in the portion 8, a front wall or panel 9. The frame is preferably made of metal, and may be formed in any way desired as for example by die casting; but it also may be formed as illustrated from sheet metal with the parts bent as shown,

Stator plates It! for the condensers are mounted. on spacer members II. There will 'be sepa- 1 rate spacer members, of course, for each condenser in the gang. The spacer members (and thereby the stator plate assemblies) are in turn mounted in the frame upon insulating supports In the frame I journal a gang condenser shaft 13. This may have a single ball thrust bearing I4 against the end piece 4, and may extend through the end piece 5 as at 53a, there being a ball and raceway thrust bearing 1'5 against the member 5. To the shaft extension l3 there may be affixed a tuning knob, or a mechanical power transmission from a direct or Vernier means for manual tuning, as will be well understood by those skilled in the art. There will usually be (also not shown) a suitable dial mechanism connected directly or otherwise to the shaft extension l3a.

The rotor blades l6 of the condenser or condensers are aflixed in any suitable way to the shaft [3. Shielding (not shown) may be employed between the condensers of the gang in accordance with the desire of-the set builder. The condenser gang construction is essentially to the condenser shaft IS, a plate i1.

housed in the box formed by frame members I 1, 4,1 and 6 in the form shown; and -it will be within the skill of the set builder to provide the box with a cover if this is deemed desirable.

The particular mechanical tuning device here illustrated is effective accurately to position the rotor assembly angularly through a range of something less than 180. denserassembly with stator and rotor plates so shaped that proper tuning coverage for the radio set is attained when the rotor plates move through an angle of approximately 60. As with the conventional type of gang condenser the skilled worker can so shape his rotor and stator platesas to cover .the correct frequency range for different angularities of movement.

For the purpose of mechanical tuning, I fasten The length of this plate may be dependent upon the number of plungers employed as will be apparent hereinafter. The plungers themselvesindicated at I! are preferably made from stampings of sheet metal and are rectangular in cross section, but they may be made in other ways and may have any desired shape.- These plungers are mounted for axial movement in correspondingly shaped perforations in the interspaced frame members 6 and 9. The perforations, however, are enlarged as at l9 to give access to the adjusting mechanism next to be described.

To the end of each plunger I pivot an actuating arm 20. The pivot point is indicated at 2|. Conveniently a rivet may be used for fastening the actuating arm to the plunger and for-pivoting it thereon. The actuating arm has contacting sur-' faces or points 22 and 23;.and it will be clear that -when the plunger I8 is moved axially so as to bring the actuating arm 20 against the plate I1 on the condenser shaft, the plate will be positioned by the arm if the position of the arm is fixed on the plunger. If, therefore, the arm is fixed on the plunger in a definite position representative of a desired tuning of the radio set, actuation of the plunger will tune the radio set.

So as to fix the actuating arm adjustably on the-plunger, I strike up or aflix cars 24 and 25 to the plunger. A set screw 26 is threaded into perforations in these ears. A locking plate 21 is perforated sothat it can be slipped over the ear 26 before the set screw is threaded into the ear. The locking plate has an angularly bent portion 28, which lies above the rounded front portion of the actuating arm 20. It will be clear that when the set screw 26 is tightened against the angularly bentportion 28 of the locking plate, the locking plate will act to bind the actuating arm to the plunger and fix its position thereon.

The plunger l8 has a reduced front portion I611, upon which a button or the like suitably marked with the indicia of the station-selected may be placed.

It will be clear that my device does not interfere with the ordinary tuning of the radio set, which may be tuned by means of the manual tuning knob and dial as is customary. But by firsttuning the set to adesired station, loosening the set screw 26 and depressing the plunger 18, the

arm 20will be given a positionon the plunger I 8 when the plunger is actuated, the condenser gang will instantly be tuned to the pre-selected'station. There may be many of the plungers l8 as desired, since it will be within the skill of the I have shown a conworker in the art to vary the longitudinal dimension of the plate 11. A coiled spring 29 may be engaged in suitable perforations in the frame member 9, and in the plunger, soas to keep the plungerin the forward position.

Modifications may be made in my invention without departing from the spirit of it. Having thus described my invention,-what -I claim as new and desire to secure by Letters Patent is:

1. In a radio set, a gang condenser, a housing therefor having interspaced front walls, said gang condenser having a movable shaft, a member attached to said shaft, plungers slidably mounted in said front walls, and means on said plungers for contacting said member.

2'.'In a radio set, a gang con'wser, a housing therefor having interspaced front alls, saidgang condenser having a movable shaft, a member attached to said shaft, plungers slidably mounted in said front walls, and means on said plungers for contacting said member, said means comprising positioning arms on said plungers, and means for holding said arms on said plungersin adjusted position.

3. In a radio set, a gang condenser, a housing therefor having interspaced front walls, said gang condenser having a movable shaft, a member attached to said shaft, plungers slidably mounted in said front walls, and means on said plungers for contacting said member, said means comprising positioning arms on said plungers, and means for holding said arms on said plungers in adjusted position, said holding means being accessible for adjustment through said front wallstructure.

4. In automatic tuning apparatus a member pivoted to turn about an axis, a plunger movable longitudinallyv in a direction transverse to said axis, said plunger having means for moving said member to a predetermined position and including means for contacting said member on both sides of its axis. and a condenser having a stator assembly externally supported and a movable assembly attached to and movable with said mem-' her, the portion of said plunger carrying said contacting means terminating at the surface of said against said member, said means being adjustable on said plunger so as to swing said member to a predetermined position and a condenser comprising an externally supported stator assembly and a rotor assembly supported by and movable with said member, said adjustable means on said plunger havingfportions extending'on either side of said axis whereby when said plunger is moved toward said member, said member will be moved by one of said portions in a given direction until stopped by contact with the other of said portions.

6. In an automatic tuning device a member pivoted to turn about one of its axes, a plunger longitudinally movable transversely to and ina direction extending through said axis, but terminating at the surface of said member when moved to; its innermost position, means for mount ing said plunger for longitudinal movement, means on said plunger for swinging said member to a determined angular position when said means is brought against said member, said means being adjustable on said plunger so as to swing said member to a predetermined position and a condenser comprising an externally supported stator 5 assembly and arotor assembly supported by and said portions, and resilient means for retracting said plunger after a positioning operation.

7. In an automatic tuning device a condenser having an externally supported stator assembly and a pivoted rotor assembly, a member attached to said rotor assembly to move about said pivot and a plunger having a portion mounted for longi-- tudinal movement transverse to and in a direction Y extending through the axis of rotation of said member and rotor assembly, mounting means for said plunger to define its longitudinal movement and means at the end of said plunger for contacting and positioning said member and said rotor.

assembly thereby on both sides of its axis.

8. In an automatic tuning device a condenser having an externally supported stator assembly and a pivoted rotor assembly, a member attached to said rotor assembly to move about said pivot and a plunger having a portion mounted for longitudinal movement transverse to and in a direction extending through the axis of rotation of saidmember and rotor assembly, mounting means for said plunger to define its longitudinal movement and means at the end of said plunger.

for contacting and positioning said member and said rotor assembly thereby, said last mentioned means being adjustable on said plunger and adapted to position said member by contact there- 40 with at opposite sides of its said axis.

9. In an automatic tuning device a condenser, a member attached to a moving part of said c'ondenser and pivoted to swing about one of its axes, and selective means acting ,upon said member for bringing said member to predetermined positions whereby to tune said condenser, saidlast mentioned means comprising plungers having portions longitudinally movable in a direction transverse to and in the plane of the axis of rotation 60 of said member and terminating at the surface thereof when moved to their innermost positions and positioning means on said plimgers for contacting said member when brought thereagainst soils to fix the position of said member by contact therewith on both sides of said axis, means for mounting said plungers, means for adiustably fixing the position of said positioning members on said plunger-s, a front panel, operating'means for said plungers extending through said front panel,

00 the adjustable means for said positioning means being accessible through said front panel.

10. In a radio set, a tunable circuit element, having a stationary section and a movable section,

a housing for said circuit element, a substantially 65 flat member iournaled at its ends in said housing for rotation about an axis, said movable section 'of said circuit element being mounted on one side of said iournaled member, a plunger slidably mounted in said housing for movement longitud- 70 inally transverse to and in a direction substantially through said axis, said plunger howeverterminating short of said journaled member when in its innermost position, a positioning member pivoted on said plunger for contacting said journaled member on the side opposite to the side supporting said movable section of said circuit element and for rotating said journaled member, said positioning member adapted to contact said journaled member on each side of its axis, and means for locking said positioning member .on said plunger 1 in adjusted position.

11. In a radio set, a tunable circuit element, having a stationary section and a movable section, a substantially flat member journaled at its ends for rotation about an axis, said movable sec- 15 tion of said circuit element being mounted on one side of said journaled member, a plunger slidably mounted for translatory movement substantially transverse to said axis, said plunger having a portion moving in a direction substantially 20 through said axis but having an end limit of motion ,short of said 'journaled member, and means on said portion for positioning said journaled member by making contact therewith at both sides ofi ts axis. 25 l2.-In a radio set, a tunable circuit element, having a stationary sectionand a movable section, a housing forsaid circuit element, a substantially flat member joumaled at its ends in .said housing for rotation about an axis, said mov- 30 able section .of said circuit element being mounted on one side of said journaled member, a plunger slidably mounted in said housing for translatory movement substantially transverse to said axis, said plunger having a portion moving in a direc- 35 tion substantially through said axis but having an end limit of motion short of said journaled member, and means on said portion for positioning said journaled member by making contact therewith on both sides of its axis. 40

13; A tuning instrument for a radio set including a frame, a stator and a rotor, said rotor comprising rotor groups of blades mounted within the frame for angular movement of approximately degrees to vary capacity throughout a complete 45 range, contact parts secured to the rotor blades, one on each side of the rotor axis and having their outer surfaces in the' same plane, manually operable members supported by the frame, an adjustable element carried by eachof said members 50 and adapted when moved by its, member, to engage said outer surfaces of said contact parts and turn the rotor to apredetermined position.

. 14. A tuning apparatus for a radioset including, a frame, a plurality of stator and rotor groups 5 of plates mounted within the frame, the rotor groups of plates being-mounted on a common shaft forming a combined rotor structure, therotor structure having means for being rotatably acted upon, manually operable units slidably sup- 50' ported by the frame} each of said units having an arcuately formed adjustable element with spaced portions to successively engage said means on the rotor structur to turn the same according to the setting of sai element, said element being held in adjusted position by side pressure, and means comprising parts of said unit for applying said side pressure to clamp said element.

HOWARD J. TYZZER. 

